The present invention relates to a solar radiation concentrating apparatus and a method for concentrating solar radiation for use in a solar heat system, a solar heat power generation system, a solar cooker, a solar furnace, a photovoltaic power generation system, a distillation device, a sunlight illuminator, a chemical reactor system, or the like.
As a background art utilizing energy of solar radiation, there is a photovoltaic power generation system, a solar heat system, a solar furnace, a distillation apparatus such as a saline water desalination system, a chemical reactor system, or a sunlight illumination system, for example.
The energy density of solar radiation is about 1 KW/m2. In operating these energy systems at a high energy density, solar radiation is concentrated. As a convergence element for concentrating solar radiation, there are a Fresnel lens, a parabolic mirror, and so forth, for example.
When solar radiation is concentrated to a solar energy conversion apparatus using a convergence optical system having such a convergence element, it is generally important to make an optical axis of the convergence optical system agree with an incident direction of solar radiation, in order to obtain a high concentration ratio. Namely, in a solar energy system having a tracking mechanism which rotates the convergence element in accordance with a variation of an incident direction of solar radiation and which makes the solar energy conversion apparatus agree with a focal point of the convergence element, solar radiation is utilized at a high concentration ratio.
In order to operate such a solar energy system for a long period of time, durability against a strong wind and so forth is required. When a height of the convergence element increases, a bad influence due to a wind pressure remarkably increases. Therefore, when a convergence element extending to a high altitude is utilized, the costs for maintaining a mechanical strength of the convergence element and the tracking mechanism increase. Thus, there has been a limit in utilizing a large convergence element.
Further, in irradiating a fixed region with solar radiation utilizing a large flat reflector and so forth, there has been a similar problem in making a large scale tracking mechanism.
As another background art, an energy system having a heliostat group is known. Such an energy system includes a plurality of flat reflectors and a plurality of tracking mechanisms which respectively drive the plurality of flat reflectors. Solar radiation reflected by the plurality of flat reflectors is concentrated to a fixed solar radiation concentration region. When solar radiation is concentrated at a high concentration ratio, many high-precision tracking mechanisms are loaded. However, the costs of the tracking mechanisms are high, and the reduction thereof is requested. Further, in using a large flat reflector, there have been problems associated with the bad influence due to the above-mentioned wind pressure or the large tracking mechanism.
As still another background art which is made from such a point of view, a sunlight convergence apparatus is disclosed in the Japanese Laid-Open Patent Publication No. 51-27347, which includes many small reflectors capable of being rotated around respective rotational centers on shafts, a controlling body, and a common link which connects each small reflector to the controlling body. Each small reflector is rotated with the same angular variation by moving the controlling body. When the controlling body is in a specified position, each small reflector is at an angle so as to reflect and concentrate a parallel light beam at a specific incident angle toward a prescribed concentration position. The sunlight convergence apparatus is designed so as to concentrate the reflected light from each small reflector to the concentration position, by controlling the position of the controlling body according to a variation of the incident angle of the parallel incident light beam.
However, in the sunlight convergence apparatus of which the whole plurality of reflectors are reviewed as a convergence optical system for concentrating solar radiation to the prescribed concentration position, there has been the problem that the concentration ratio is remarkably deteriorated with the increment of the variation of the incident angle of the incident light. However, such a decrease in the concentration ratio is not referred to in the Laid-Open Patent Publication No. 51-27347, and the teaching for overcoming this is not disclosed.
The present invention is made in view of the above, and an object of the present invention is to provide a novel solar radiation concentrating apparatus and a method for concentrating solar radiation, which realize a high concentration ratio for a wide range of the incident angle of incident light, and which collectively drive a plurality of reflectors.
Another object of the present invention is to provide a novel solar radiation concentrating apparatus and a method for concentrating solar radiation which utilize solar energy at a high concentration ratio.
Another object of the present invention is to provide a novel solar radiation concentrating apparatus and a method for concentrating solar radiation, having a high solar radiation collecting efficiency.
Another object of the present invention is to provide a novel solar radiation concentrating apparatus and a method for concentrating solar radiation at a low-cost.
Still another object of the present invention is to improve the durability of a solar energy system against an external environment such as a wind in a solar radiation concentrating apparatus.
According to an embodiment of the present invention, a novel solar radiation concentrating apparatus is provided. The solar radiation concentrating apparatus includes a plurality of reflectors for reflecting incident solar radiation along a prescribed incident direction region, a plurality of reflector vertical bars which are respectively connected to the plurality of reflectors, a center of rotation providing member which defines respective central points of rotational movements of the plurality of reflector vertical bars, a moving member for collectively rotating the plurality of reflector vertical bars, and a guide member which guides the movements of the plurality of reflector vertical bars so that the plurality of reflector vertical bars are rotated along respective prescribed reflector vertical bar orbits. The plurality of reflectors are arranged on a reflector arrangement surface. The moving member is moved with a prescribed moving member orbit in accordance with a variation of incident angle of the incident solar radiation. A hole is bored through the moving member along a curve corresponding to a track which is drawn on the moving member by the points of intersection between the moving member being moved with the prescribed moving member orbit and the plurality of reflector vertical bars being moved with the respective prescribed reflector vertical bar orbits. The plurality of reflector vertical bars are capable of being moved along the hole. The hole may be plural. Thus, reflected solar radiation reflected by the plurality of reflectors is concentrated to a prescribed concentration region at a high concentration ratio.
A guide hole having a prescribed shape for guiding the plurality of reflector vertical bars in a slidable state may be bored through the guide member.
The solar radiation concentrating apparatus may further include a rotational mechanism. The rotational mechanism rotates the plurality of reflectors, the plurality of reflector vertical bars, the center of rotation providing member, the moving member, and the guide member around a straight line perpendicular to the reflector arrangement surface so that a projection of the incident solar radiation is caused to be parallel to a prescribed incident direction indicating line defined in the reflector arrangement surface.
The moving member may define respective positions of the plurality of reflector vertical bars with respect to a direction approximately along the incident solar radiation. Further, the guide member may define respective positions of the plurality of reflector vertical bars with respect to a direction approximately perpendicular to the incident solar radiation.
The moving member may include a link and a plurality of rotating body which are collectively rotated by the link and which rotate the plurality of reflector vertical bars. Alternatively, the moving member may be a flat board member.
The solar radiation concentrating apparatus may further include a floating body.
According to another embodiment of the present invention, a novel solar radiation concentrating method is provided. By the method for concentrating solar radiation, a solar radiation concentrating apparatus is driven, which includes a plurality of reflectors arranged in a reflector arrangement surface and for reflecting incident solar radiation along a prescribed incident direction range, a plurality of reflector vertical bars respectively connected to the plurality of reflectors, a center of rotation providing member defining respective central points of rotational movements of the plurality of reflector vertical bars, a moving member for collectively rotating the plurality of reflector vertical bars, and a guide member for guiding the movements of the plurality of reflector vertical bars so that the plurality of reflector vertical bars are rotated along respective prescribed reflector vertical bar orbits, for concentrating reflected solar radiation reflected by the plurality of reflectors to a prescribed concentration region. The method for concentrating solar radiation includes a step of rotating the solar radiation concentrating apparatus around a straight line perpendicular to the reflector arrangement surface so that the incident solar radiation is incident along a prescribed direction in the reflector arrangement surface and a step of positioning the moving member to a prescribe position defined in accordance with an incident angle of the incident solar radiation.